Starch making system



D80 1935- F. L. JEFFERIES 2,065,313

STARCH MAKING SYSTEM Filed April 26, 1933 2 Sheets-Sheet 1 6724012 7/028! 156k] [2 /72 14 6&4 F 31 [bursa ab;

Patented Dec. 22, 1936 PATENT. OFFICE STARCH MAKING SYSTEM Frederick L. Jefleries, La Grange, Ill., assignor to International Patents Development Company, Wilmington, Del., a corporation oi Delaware Application April 26, 1933, SerialNo. 668,097 1 Claims. (01. 127-69) This invention relates to the manufacture of starch from corn by the wet method in which, according to common practice, the corn after being steeped in water containing sulphur dioxa ide, is subjected to separating operations in water for removal of the germ, bran or hull and fiber, the process at this stage, (the wet starch system) being divided, commonly, into three operations called germ, coarse slop and fine slop separations, after which the resultant mixtures of starch, gluten and water, (mill starch) are combined and run through shallow, slightly inclined troughs (starch, tables), or otherwise treated for the separation of the gluten and bulk of the water from the starch; the starch remaining on the tables and the gluten water tailing off therefrom. This tabling operation is followed, ordinarily, by settling the gluten out of the table eiliuent in vats (gluten settlers). The starch is removed from thetables, for example, by flushing with water, and may be subjected to one or more washing operations usually in vacuum or pressure filters of the displacement type. The mill starch stream, made up of the 5 three streams from theseparating operations above referred to, has had, ordinarily, a density at the tableheads between 5 and 7 Baum.

It has been customary to use a minor portion of the water from the gluten settlers (gluten water, which liquid contains relatively large quantities of corn solubles, micro-organisms and other impurities, for steeping the corn, and to draw oil the steep water and evaporate it for the purpose of saving the soluble substances of the corri therein which have considerable value. The amount of gluten water which can thus be used for steeping is limited, for economic reasons, by the cost of evaporationci the steep water which, if too dilute, will not pay to evapcrate. The customary steep water draw-oil? is about '7 gallons per bushel of corn, ground-all water computations referred to herein being upon the basis of bushels of corn ground and treated in the process. A larger steep water draw-01f would entail a proportionately higher expense for evaporation; and somewhere a point of maximum practical draw-off is reached, be-

yond which the cost of evaporation exceeds the value of the evaporated product.

It has also been'customary to re-use the rest of the gluten water-the major portion of it-- in the wet starch system, that is in the germ, coarse slop and fine slop separations, in the place of fresh water; and to use in the same 55 operations, as make-up water, wash water or filtratefrom the starch washing filters; and a starch making system so operated has been called iniactory parlance afbottled-up system." Such a system is disclosed in U. S. patent to Rush 0. McCoyNo. 1,651,611, patented Decemher 6, 1927.

A bottled-up system effects complete saving of the corn substance-soluble and insoluble-- in the, process waters, economizes water and prevents s'tream'pollution, as no process water need be sent into rivers or lakes via the factory sewers; but the re-use of the gluten water in the wet starch system, forming a part of this process, is objectionable because it takes back into the system thev relatively large quantities of soluble substances in the gluten water, together with the micro-organisms and products of micro-organic activity developed in such water in its passage through the various stages of the process and during the period of standing in the gluten settlers, and these non-starch bodies and substances constitute and give rise to impurities in the starch, some of which impurities appear to be of a colloidal character,difllcult to remove by washing. The excess of solubles necessarily insystem, during a given period of time, will all be drawn off during its passage through the systern. On the contrary, an indeterminate portion of any given volume of returned process water may .be re-circulated, with its solubles, micro-organisms and their products, for an indefinite number of times, and thus a certain number of micro-organisms may remain and thrive in the system for a long period; and this condition necessarily brings about an increased quantity in the starch of such impurities as are the result of micro-organic activity. That is, as in any cyclic system, an indeterminate part of the process water may remain in the system for a long time and thereby increase the infection of the system.

Applications of Frederick L. Jeiiries, Serial No. 606,897, filed April 2, 1922 (Patent No. 2,050,330,

August 11, 1936), and Serial No. $368,095, filed back to the wet starch system. Contamination of the materials in process in thereby minimized.

These improved processes involve making the separation between starch and gluten, by tabling or equivalent operation, at much higher densities made to any invention disclosed in the aforementioned applications 606,897 or 668,095 has for its object certain modified arrangements whereby the same general object-excli1sion of the gluten water from the wet starch system-- is accomplished by specifically difl'erent expedients. The present invention contemplates, specifically, the use in the process of a concentrating device which not only extracts water from the mill starch but which also effects a separation between the starch and the gluten in the mill starch or a portion of the same. This arrangement makes possible a reduction in steep water draw-01f, reduction in table equipment and simplification of the process of washing the starch in the starch filters.

A particular object of the present invention. of value regardless of the extent to which process waters are returned for re-use in the process, is to provide certain novel arrangements whereby the tabling or other apparatus for making the separation between the starch and gluten may be reduced and this operation facilitated and the cost of the same lessened.

This object is carried out by subjecting the mill starch, or a portion of the same, to a preliminary separating operation in a settling vessel from which a certain amount of starch may be withdrawn in condition, after the usual washing, for sale or use; after which the rest of the mixture in the settling vessel, consisting of starch, gluten and water, either alone or mixed with mill starch, is subjected to a tabling operation, or its equivalent, for completing the separation of the gluten from the starch. This operation may, under some circumstances, result in too high a gluten content in the starch and in such case the starch may be flushed or otherwise washed from the tables and returned to the process, for example, to the settling vessel, for treatment with the incoming mill starch. Under other conditions the starch will be free enough from gluten so that it may go directly to the washing filters.

The invention is shown in two preferred embodiments in the accompanying drawings, designated Figs. 1 and 2, which are fiow sheet diagrams of the improved processes.

The numerals on the drawings followed by the abbreviation Gal. indicate water content in terms of bushels of corn ground and operated on. By impurities are intended all non-starch substances in the material, except the germ, gluten and slop (hull, bran and fiber), and includes corn solubles and other solubles, microorganisms, enzymes and their products, and any residual insolubles and colloidal matter in the process waters and in the starch. By mill starch is intended the mixture or mixtures of starch, gluten and water derived from the germ, coarse slop and fine slop separations. By gluten water is intended the primary process water containing the largest quantity of impurities, whether this water be removed from the system after settling out of the gluten in gluten settlers or otherwise at that or at an earlier stage of the procedure. Where reels or shakers are shown and referred to as such either type of sieving apparatus may be substituted for the other, or other equivalent separating devices may be used. By wet starch system are intended the germ, coarse slop and fine slop separating operations. The starch is shown as flushed from the tables but may be removed by any customary mechanical means. The term fresh water" is used, necessarily, in a relative sense. All water contains some solubles and impurities. By "fresh water is intended either water from the service pipes, wells, etc., or process water containing very small quantities of solubles or other impurities in comparison with the quantities of substances in the materials treated by such water. The term pipe is intended to include any suitable conduit or conveyor.

Referring first to Fig. 1, A represents one of the steep tanks of the steeping system, this system consisting, ordinarily, of a number of tanks in which the corn is steeped with water containing sulphur dioxide at temperatures ordinarily above room temperature. The steep water is drawn oil. to evaporators which are not shown. The steeped corn is coarse ground in mill B, the germ separated by flotation from the rest of the material in separator C and washed in germ washing system D, which latter consists of a series of reels and/or shakers. The de-germinated corn is put through a reel E to remove the slop, and the liquid magma passing over E is put through a shaker F to remove the grits, i. e., starch particles; and slop and grits are ground in mill G. The ground material is washed in the coame slop washing apparatus H consisting of a system of reels and/or shakers operated on the countercurrent principle. The liquid from the coarse slop wash containing starch, gluten and fine bran particles, is passed over a sieve I for intercepting the fine bran particles, which latter are washed in the fine slop washing system J confrom the germ separation and contains the largest quantity of soluble substances as well as the largest quantity of insolubles, starch and glutten. The mill starch in pipe y, derived from the coarse slop wash, contains less solubles and insolubles than the stream .1: but considerably more than the mill starch stream in pipe 2: which is derived from the fine slop wash. The stream in z is quite dilute. The mill starch of the z stream is run into a concentrating and separating apparatus N of any suitable type, such as a Dorr thickener, which separates some of the starch from the gluten and eliminates some 01 the water from the gluten-starch mixture. This eliminated water is returned to and re-used in the wet starch system, the starch separated out is sent to the starch filtering system for washing, the mixture of starch and gluten then goes to a mixing vessel U into which the mill starch streams x and y are introduced, and the mixture from the tank U is sent over the starch tables 0. The starch settles on the tables 0, the gluten and water tails off into the gluten settler T, the gluten from which is pressed in the press Q. The starch removed from tables 0 is washed first in the filter R and then in the filter S. The

starch from the concentrator-separator N is preferably washed only in the second filter S,

I although this is optional. T is a dilution tank for diluting the starch from filter R before it mill B and the ground material through pipe is to separator C. The germs floated in the separator pass through pipe H to the germ wash D, the liquid from which passes back to the separator through pipe IS. The germs containing 0.5 gallon of water are discharged from the system at It. The degerminated corn passes from the separator C through pipe 11 to reel E,

and the slop from reelE goes through'pipe l8 to mill G. The liquid from reelEpasses through pipe [6 to shaker F, the grits going from the shaker through pipe 20 to mill G. The slop and grits ground in mill G pass through pipe 2| to the coarse slop wash. The coarse slop containing 0.6 gallon of water is discharged from the system at 22. The liquid from the coarse slop wash passes through pipe 23 to shaker I. The fine slop from the shaker I containing 5.6 gallons of water passes through pipe 22 to the fine slop wash J. The fine slop, containing 0.3 gallon of water is discharged from the system at 25.

The mill starch from the fine slop wash containing 13.6 gallons of water passes through pipe 2 to the separator-concentrator N which classifies the material into, preferably, three strata, starch in the lower part of the apparatus, substantially free from gluten, which, with 1.8 gallons of water passes through pipe 26 to the second filter S; water in the upper part of the apparatus (this may, of course, contain small quantities of starch and gluten) which, to the extent of 9.5 gallons, passes into pipe 21, 7.5 gallons going to the germ wash and 2 gallons going through pipe 28 to the coarse slop wash; and a middle stratum of starch and gluten which is,

drawn oil through pipe 29 to the mixing vessel U, into which are also discharged 7.5 gallons of mill starch from pipe :1: and 6.8 gallons from p p 1. l

The mixture of mill starch in the vessel U, 16.6 gallons inall, is passed over the starch tables 0, the water and gluten passing through pipe 30 to the gluten settlers P. The gluten water, 13 gallons. is sent to the steeps through pipe (ii. The settled gluten passes through pipe 32 to press Q, the water from the press going through pipe 33 to the gluten settler. The gluten, containing 0.7 gallon of water, is discharged from the system at 34. i

The starch flushed from the tables by 4.6 gallons of water delivered through pipe 35 passes through pipe 36, with 7.2 gallons of water to the first filter R. Here it is de-watered and then washed with 2.5 gallons of fresh water from pipe 31. The filtrate from the first filter, 7.3 gallons, passes into pipe 33, 6.1 gallons going into the coarse slop'wash and 1.2 gallons through branch ;branch pipe 4| of the fresh water supply pipe 31. The diluted starch passes through pipe 42 to the second filter S where it is de-watered and then washed, (together with the starch from concentrator N through pipe 26) with 3.0 gallons of fresh water through branch pipe 43. 7.1 gallons of the filtrate from the second filter S passes into pipe 44 and thence to the fine slop wash. 1.5 gallons goes into the flushing water pipe 35, above mentioned, being augmented by three gallons of fresh water from the branch pipe 45. The starch is discharged from filter S' at 46 and contains 3.1 gallons of water.

The above mentioned water balance figures are merely illustrative and typical. .They depend,

necessarily, upon the particlar apparatuses employed.

The process of Fig.2 is the same as that of Fig. 1 as far as the concentrator-separator N;

and to this point the elements of the apparatus and their connections are given reference characters corresponding with the reference characters usedin Fig. 1. In the Fig. 2 arrangement there are two sets of tables: high solubles tables 0 for tabling the a: and 1! mill house streams from the gem and coarse slop separations and low solubles" tables 0, for tabllngthe over-flow from the concentrator-separator N.

The gluten water from the gluten settler P receiving the eiiiuent from tables O-this being the steeps while the ,over-flow from the gluten settler P receiving the eiliuent from the low solubles tables O'-a'- liquid having a relatively low solubles content-is re-used in earlier stages of the process.

The washing of the starch is the same as in Fig. 1 (except that the water quantities are preferably adjusted to the difierent conditions) as indicated onthe'drawings, and the elements of the washing system and their connections are given the same reference numeralsas are used in Fig. 1.

The amount of steep water withdrawn from the steeping system at II is reduced to 7 galions by a reduction of gluten water from settler P through pipe 3| to the steeps to 11.2 gallons. This makes it possible to introduce into the systern, through pipe 31, only 11.2 gallons of fresh water as indicated.

The starch separated in the concentrator-separator N passes through pipe 26, with 2.2 gallons of water, to the second filter S. The over-flow from the concentrator-separator N consisting of a very dilute mixture of gluten with some starch in it, 12.4 gallons, passes through pipe 41 to a collecting vessel U and from this to the low solubles tables 0. The starch settles on the tables and the gluten and water passes through pipe 48 to the gluten settler P. The gluten from the gluten settleris pressed in the press Q; the water going back to the gluten settler through pipe 49 and the gluten, containing 0.2 gallon of water, being discharged from the system at 50. The water from the gluten settler P, 12.5 gallons, passes into pipe 5i, 7.5 gallons going to the germ wash D and 5.0 gallons going to thecoarse slop wash through branch pipe 52.

The starch is flushed from the tables 0'. with 1.3 gallons of fresh water from branch pipe 53 of the fresh water supply pipe 31; and, as this starch is relatively impure, containing a certain amount of gluten, it is preferably returned, containing 15 gallons of water, to the concentratorseparator N through pipe 54; although it could be discharged from the system if the relatively In this case the starch could be washed in filters as usual.

ihe 6.5 gallons of filtrate from the first filter R passes into pipe 55, 3.1 gallons going to the coarse slop wash H and 3.4 gallons through pipe 56 to the fine slop wash J. Of the 8.7 gallons entering pipe 51 from the second filter S, 4.9 gallons goes to the fine slop wash J and 3.8 gallons through pipe 58 to the flushing system for the high solubles tablesO.

While the process as disclosed involves no discharge of process waters to the sewer, circumstances might require a discharge to the sewer of a greater or lesser quantity of water; and in this case it would be desirable to discharge some or all of the water from the gluten settler P as this water is very low in solubles. In such case the amount of fresh water introduced into the system might have to be increased.

It would be understood that both as to the processes of Figs. 1 and 2, the water balance quantitit; can be varied considerably and would probably have to be varied for different installations, and possibly for differentoualities of corn handled. Such modifications are contemplated by this invention, and the intention is to cover all variants within the scope of the appended claims.

I claim:

1. In the process of obtaining starch from corn: separating from the ground corn in water a mixture of starch, gluten and water; bringing about a separation in a settling vessel of some of the starch in said mixture; tabling the residue to eliminate the gluten from the starch; flushing the starch from the tables; and returning the flushed starch to said settling vessel.

2. In the process of obtaining starch from corn: separating from the ground corn in water a mixture of starch, gluten and water; bringing about a separation in a settling vessel of some of the starch in said mixture; tabling the residue of the mixture to eliminate some of the gluten from the starch; removing the starch with its residual gluten from the tables; and returning such starch to the process for further separation of gluten therefrom.

3. In the process of obtaining starch from corn comprising tabling mill starch to separate the gluten therefrom: the improvement which consists in bringing about a settling out of some of the starch from the mill starch in a settling vessel; subjecting the residue to the tabling operation; flushing the starch from the tables; and returning the flushed starch to the settling vessel.

4. In the process of obtaining starch from corn in which the corn, in a comminuted state, is subjected to separating operations yielding a water mixture of starch and gluten the improvement which consists in subjecting said water mixture of starch and gluten to an operation which separates therefrom part of the starch substantially free from gluten and in a concentrated but fluent state; returning and re-using in said separating operations on subsequently treated comrninuted corn a dilute mixture of water and solids derived from the separating op eration performed on said water mixture; and subjecting the rest of the starch and gluten mixture to a separating operation for removing the gluten.

5. In the process of obtaining starch from corn the improvement which consists in subjecting mill starch to an operation which divides the same into (1) starch substantially free from gluten, (2) a dilute mixture of gluten, water and starch, and (3) water containing a small quantity of solids; re-using in the process said water; and separately treating the starch and gluten mixture to separate the gluten from the starch.

6. In the process of obtaining starch from com the improvement which consists in subjecting mill starch to an operation which divides the same into (1) starch substantially free from gluten, (2) a dilute mixture of gluten, water and starch and (3) water containing some solids; re-using said water in the process; separately treating the starch and gluten mixture to separate the gluten from the starch; and filtering the starch from both said operations for removing the solubles therefrom.

7. In the process of obtaining starch from corn comprising subjecting the corn in a comminuted state in water to germ, coarse slop and fine slop separating operations: the improvement whichconsists in subjecting the mill starch from the fine slop separation to an operation which separates out some of the starch, substantially free from gluten, and separately eliminates a mixture containing the bulk of the gluten, some starch and water, and also water containing small quantities of solids; mixing the starch and gluten mixture from said operation with the mill starch from the [term and coarse slop separations; treating the mixture to separate the gluten from the starch; and returning the water derived from the aforesaid operation to and re-using it in the process.

8. In the process of obtaining starch from corn comprising steeping the corn and subject-' ing it in a comminuted state in water to germ, coarse slop and fine slop separations: the improvement which consists in treating the mill starch from the fine slop separation to separate the same into (1) starch, (2) a mixture containing the bulk of the gluten, some starch and water, and (3) water containing small quantities of solids; returning the said water to the process for re-use; incorporating the starch and gluten mixture with the mill starch from the germ and coarse slop separations; and treating this mixture to separate the starch and gluten; returning the gluten water to and re-using it in the steeping operation; washing with fresh water the starch recovered in the aforesaid operations; and re-using the starch wash water in the process.

9. In the process of obtaining starch from corn: the improvement which consists in subjecting mill starch to an operation for recovering a portion of the starch substantially free from gluten; separately treating the residue to extract gluten therefrom; diluting with water the starch material derived from the last mentioned operation; and mixing the diluted starch with fresh mill starch as the process proceeds for treatment as aforesaid.

10. In the process of obtaining starch from corn: the improvement which consists in subjecting mill starch to an operation for removal therefrom of some of the starch substantially free from gluten; tabling the residue to remove gluten; flushing the tabled starch; and mixing the flushed starch with mill starch to be treated as aforesaid.

11. In the process of obtaining starch from corn comprising subjecting the corn in a comminuted state in water to germ, coarse slop and fine slop separation operations: the improvement which consists in treating a mill starch from the fine slop separation in a settling vessel to recover some of the starch therefrom; ta'oling the rest of this mill starch; flushing the starch from the tables; and mixing the flushed starch with mill starch to be treated as aforesaid.

12. In the process of obtaining starch from corn comprising steeping the corn and subjecting it in a comminuted state in water to germ, coarse slop and fine slop separations: the improvement which consists in subjecting the mill starch from the fine slop separation to a settling operation for removal of some of the starch substantially free from gluten; tabling the rest of such mill starch; flushing the tabled starch aforesaid; tabling the mill starch fromthe germ and coarse slop separations; re-using the gluten water from the last named tabling operation for steeping corn; washing the starch and reusing the starch wash water in the process.

13. In the process of manufacturing starch from corn comprising steeping the corn, comminuting the steeped corn, subjecting the comminuted corn to separating operations in water yielding mixtures of starch, gluten and water having different solubles contents: the improvement which consists in removing starch and gluten from the mixture of starch, gluten and water having the higher solubles content and i'e-using water from said mixture for steeping corn; subjecting the mixture of lower solubles content to an operation which removes therefrom" starch, substantially free from gluten, and water, substantially free from solids; and reusing the water from said last named mixture for said separating operations.

14. In the process of manufacturing starch u from corn comprising steeping the corn, comminuting the steeped corn, subjecting. the comminuted corn to germ, coarse slop and fine slop separations in water, yielding separate mill starch streams: the improvement which consists in subjecting the mill starch from the fine slop separation to an operation which removes therefrom starch, substantially free from gluten, and water, substantially free from solids; l'e-using the water from the mill starch derived from the fine slop separation for separating operations on subsequently treated comminutcd corn and re-using water from the rest of the mill starch, after removal of the starch and gluten therefrom, for steeping corn as the process is continued.

15. In the process of manufacturing starch from corn comprising steeping and comminuting the corn, subjecting it to separating operations in water, treating the mill starch from the separating operations to recover starch and gluten, and re-using water from the mill starch and mixing it with mill starch for treatment, as--=='-- in 'the process: the improvement which consists in extracting water from the mill starch before it is treated for the recovery of starch and gluten, and by the same operation removing from it some of its starch, substantially free from gluten; re-using the water thus extracted in separating operations on subsequently treated comminuted corn; and using the water left after the recovery of the starch and gluten from the mill starch for steeping com. I

16. In the process of manufacturing starch from corn comprising steeping and comminuting the corn, subjecting it to germ, coarse slop and fine slop separations, treating the mill starch from the separating operations to recover starch and gluten, and re-using the water from the mill starch in the process: the improvement which consists in extracting water from the fine slop mill starch and by the same operation removing from it some of its starch, substantially free from gluten; re-using the water thus extracted from the fine slop mill starch for separating operations on subsequently treated comminuted corn; and using the water left after recovery of starch and gluten from the mill starch for steeping corn as the process is continued.

FREDERICK L. J EFFERIES. 

